Lets just say for the sake of a good example that your opponent has 97 nonland permanents on the battlefield all having different names, and you have 3 oblivion rings on the battlefield exiling 3 of your opponents nonland permanents, again, all with different names. You have to find a way to get rid of every single one of those nonland permanents before your next turn. In hand you have 2 cards, Detention Sphere and Oblivion Ring.

While it's mostly better than o-ring, the only really consistent thing this will do better than o-ring is hit tokens that put many into play at once. With bonfire still running rampant, that shouldn't happen too often in standard.

If you have the money then this is worth it over o-ring, but at the same time if it's out of your budget it's still okay to run o-ring.